Ions are typically implanted in workpieces at a zero incident angle, where a zero incident angle represents an implant that is perpendicular to the surface of the workpiece. However, in certain semiconductor manufacturing processes, it is advantageous for the ions to strike the workpiece at a non-zero incident angle. Typically, ions are extracted from an ion source through an extraction aperture. One technique to extract ions at a non-zero angle is to install a blocker within the ion source near the extraction aperture. The blocker modifies the plasma sheath within the ion source, such that the ions are extracted at non-zero incident angles.
In certain embodiments, the blocker is held in place within the ion source through the use of screws and washers. For example, holes are disposed on either side of the extraction aperture. A fastener passes through the hole and enters a hole in a respective end of the blocker. The fastener is held in place through the use of a clasp, washer or other device. The fastener may be a screw, bolt or other suitable device.
In some cases, the fastener or the clasp may be affected by the plasma and ions within the ion source. For example, material from these components may be sputtered and subsequently enter the extracted ion beam and be accelerated toward the workpiece.
Therefore, it would be beneficial if there were a system for holding the blocker in place that did not cause contamination of the ion beam. Further, it would be advantageous if the system exhibited improved thermal characteristics.